The present invention refers to a method for making stiffening elements, made by co-curing technique, for structures made of composite material, comprising at least a hollow section.
The co-curing or co-polymerization technique is able to entirely polymerize some parts of structures made of composite material in a sole polymerization cycle.
There are known processes of production of structures made of composite material wherein lamination spindles are used. These structures are normally made in polymeric material and are used for the making of rigid panels comprising hollow elements.
These spindles are arranged on the structure for being covered by rolled sections, normally made of carbon, which determine the stiffening of this structure.
In this solution, the spindle enters in direct contact with the rolled sections, used for the stiffening of the structure, both during the posing and during the stiffening phase, normally in autoclave.
With this method, it is then really difficult the extraction of the spindle from the hollow elements after the heating of the structure, causing also high costs for the cleaning of the hollow elements made in this way.
Furthermore, the contact between the spindle and the rolled section can cause a contamination of the rolled section itself, which can vary its physical and structural characteristics causing a reduction of the performances of the rolled section in relation to the stiffening.
A further drawback of the known art is related to the impossibility of moving the spindle after the posing of the rolled sections on the structure made of composite material, because the polymeric material of the spindle usually creates a high coefficient of friction with the rolled section.